Reliability of Cathodic Protection System
Posted: 04 Apr 2010, 10:22
What are the main checks to be applied for assuring health of Cathodic Protection System? Can anybody enlist the same? Any code reference would help in great deal.
Cathodic protection system is usually employeed for the protection of underground piping systems against corrosion. Regular check up of Cathodic protection system is very necessary as its malfunctioning / improper health has a direct link with intwgrity of underground piping. Following checks are usually employeed for the health check up of any cathodic protection system.
1)- Pipe to Soil potential Survey @ a frequency of 3 months (less or more frequency can be employeed depending on the conditions & as per owner's descretion)
2)- Rectifier output current & voltage to be measured @ a frequency of 2 months (less or more frequency can be employeed as per owner's descretion)
3)- Anode bed current to be measured @ a frequency of 2 months (less or more frequency can be employeed as per owner's descretion)
4)- For cross country pipelines or plant underground piping which have isolation flanges shall be checked for any current leaks & any descripency shall be rectified. Frequency of this check shall be defined by owner himself. However, in many industries it is practiced at a frequency of 6 ~ 12 months.
5)- Proper upkeep of Cathodic protection posts is also mandatory.
For details one can refer NACE standard RP0169-20002 Standard Recommended Practice (Control of corrosion on underground or submerged metallic piping systems.